1. Field of the Invention
The present invention relates to a method for transplanting human or animal teeth, including mature or retained teeth, from one site to another in the mouth while eliminating the risk of ankylosis and root resorption. More specifically this method involves extracting human or animal teeth from their alveolar site of origin, reinserting said teeth into their original site and stabilizing the extracted teeth with sutures. After waiting a sufficient period of time to create a biological stimulation on the periodontal ligament due to the healing process, the extracted tooth is then transplanted in the receiving alveolus. This waiting period to achieve this biological stimulation is between about 5 and 30 days, preferably 15 days.
2. Brief Description of the Prior Art
Auto-transplantation is known in the art as a process wherein a tissue or organ is transferred by grafting the tissue or organ in the body of the same individual. In the case of dental auto-transplantation, a tooth located in one alveolus or tooth socket is transferred to a new alveolus.
Auto-transplantation of teeth has been carried out for many years by dentists, but with varying success rates. Numerous parameters and criteria have been studied and evaluated to obtain better results using various dental transplantation protocols.
It was known in the art that successful auto-transplantation of teeth can be obtained when the healing process gives a normal periodontal ligament (PDL) on the entire surface of the tooth's root, a normal epithelial attachment and collagenic "apparatus" at the gingival level. Auto-transplantation has been carried out for many years, but with varying success rates, and periodontal ligament (PDL) healing has been identified as a key success factor in order to avoid ankylosis and root resorption phenomenon. When these objectives are achieved, the auto-transplantation is generally successful in the long run. On the other hand, if the healing process generates lasting areas of inflammation and an ankylosis phenomenon, auto-transplantation prognosis will be poor or limited in time. Ankylosis causes the root of the tooth to be absorbed by the jawbone.
In order to reduce inflammation and ankylosis during auto-transplantation and thus improve the chances of success of this method, several factors were already known in the art of dentistry.
Thus, the first factor that was known in the art was that the tooth needs a live normal periodontal ligament (hereinafter referred to as PDL) around its entire surface when it is put in place into the new alveolus. This means that the root surface should not be traumatized by overpressure or contact with any surgical tools, and that it should not dry out by staying in ambient air during the transplantation surgery for too long. See, for example, Van Hassel et al., Endod Dent Traumatol.; 6:506-508 (1980); Bromlof et al., Scand J Dent Ros., 8:441-445 (1980); Nyman et al., J. Clin Periodontal., 7:394-401 (1980); Andreasen J. O. et al., Endod Dent Traumatol. 2:76-89 (1995); Oikarinen K S, et al., J. Periodontal Res., 5:337-44 (1996); and Trope M, et al. Endod Dent Traumatol., 4:171-5 (1997).
The second factor was that the alveolus in which the tooth is transplanted must be large enough so that there is no pressurized contact between the alveolus and the tooth to be transplanted. The PDL should not be compressed and should be fed by blood. Cells from the bone tissue should not contact the roots of the teeth that would facilitate ankylosis. Furthermore it was known that PDL cells during transplant have an osseogenic potential capable of adapting to a too wide alveolus. See, for example, Oswald et al., J. Endod; 6:479-484 (1980); Trope M, et al., Endod Dent Traumatol. 4:171-5 (1997);
Moreover, it was known that the preparation of the alveolus 14 days prior to transplantation improves vascularization of the site and results as described in Nethander et al., Int J. Oral Maxillofac Surg., 17:330-336 (1988).
The third factor known in the art was that the pulpal state of immature teeth, with an open apex, could be preserved and kept alive after transplantation. However, the pulp of mature teeth, with a closed apex, often get necrosed after transplantation. Necrotic or infected pulpal tissue is the cause of inflammatory processes that in turn will provoke root resorption.
Moreover, it was known that endodontic treatment can be performed within 10 to 20 days after transplantation to avoid inflammatory resorption. Filling is done preferably with Ca(OH).sub.2 at this stage. Andreasen J. O. Swed Dent J.,; 4:135-144 (1980); Andreasen J. O., Swed Dent J., 7:245-52 (1981) and Swed Dent J., 8:135-144 (1982); Trorstad et al., J. Endod., 8:17-22 (1981).
Furthermore, it was also known that splinting of the transplanted tooth should never be rigid, but should allow limited movements of the tooth and thus a functional stimulation. If a rigid splint is needed it should be restricted to 4 weeks. Andreasen J. O., Acta Odontol Scand., 33:313-323 (1975); Andreasen J. O. Int J. Oral Surg., 12:239-249 (1983); Berude J. A. et al., J. Endod., 14:592-600 (1988); Oikarinen K. Endod Dent Traumatol. 6:237-50 (1990); Gupta S, et al. J Clin Pediatr Dent. 22(1):19-21 (1997); and Mandel U, et al. Arch Oral Biol. 34(3):209-17 (1989).
It was also known that systemic antibiotic therapy significantly reduces root resorption. Hammarstrom L.et al., Endod Dent Traumatol., 2:51-59 (1986) and Sae-Lim V, et al. Endod Dent Traumatol., 14(5):232-6 (1998).
Thus, in the prior art the protocol for auto-transplanting a tooth involved the procedural steps of antibiotherapy treatment, local anesthesia of the tooth, extraction of the tooth to be replaced, preparation of the alveolus (curettage, enlargement), extraction of the dental transplant without tool impact on the root surface, placing the transplanted tooth into the alveolus at a level identical to the previous tooth and using a suture splint for immature teeth, while for mature teeth a wire stabilized by a composite was utilized.
After the auto-transplantation was performed, post surgical X-rays were generally taken.
Several follow up cessions at various time intervals were then performed. For example after 8 days the sutures were removed; at 21 days the splint was generally removed and the root canal was then filled with Ca(OH).sub.2 if the tooth was mature. After 28 days X-rays were again taken and a check up of root resorption risk was usually performed. After 8 weeks X-ray control was performed. After 6 months the transplanted tooth or teeth were checked to determine whether the Ca(OH).sub.2 filling was in order or final filling was completed. This latter procedure is again performed after 1 year.
Thus, it can be concluded from the above that auto-transplantation of a tooth or teeth by the prior art methods was a long and tedious procedure requiring frequent monitoring of the patient after transplantation.
Unfortunately, the outcome of the procedures taught in the prior art was not that successful and it has been shown that after 5 years on mature teeth, healing with normal PDL and without ankylosis-root resorption occurred in only 12% of transplanted Molars, in 62% of transplanted Premolars and in 48% of transplanted Incisors. See, Andreasen J. O. Atlas de reimplantation et de transplantation dentaires, Editors Masson, (1992); Andreasen J O, et al., Eur J Orthod., 12(1):3-13 (1990); and Andreasen J O, et al., Eur J Orthod. 12(1):25-37 (1990).
Therefore, a need still remains in the dental art to provide a method for transplantation of teeth that will reduce or eliminate ankylosis and root resorption and therefore result in a higher tooth transplantation success rate.
Thus it is an object of the present invention to improve the success of auto-transplantation for teeth in animals or humans.
It is a further object of the present invention to provide a process for eliminating the risk of ankylosis and root resorption after auto-transplantation of teeth.
It is a further object of the present invention to create a biological stimulation of the periodontal ligament, thus aiding in reducing the risks of ankylosis and root resorption.
It is yet a further object of the present invention to provide various suturing techniques that will aid in reducing the risks of ankylosis and root resorption.
In yet another further aspect of the present invention is to provide a method for stimulating desmodonts.
In yet a further aspect of the present invention is to provide a method for regenerating the tooth alveolus ligament, particularly on a retained tooth.
In another aspect, the present invention further provides a method for regenerating bone around a human or animal tooth and more particularly an alveolus bone or a collateral bone in any osseus site.
In yet another aspect, the present invention provides a method for stimulating bone formation.
These and other objects are achieved by the present invention as evidenced by the summary of the invention, description of the preferred embodiments and the claims.